Art of dewaxing hydrocarbon oils



Patented Mar. 26, 1935 ART OF DEWAXING HYDROCARBON OILS Edward John Martin, Hammond, Ind., assignor to Sinclair Refining Company, New York, N. Y., a corporation of Maine No Drawing. Application August 8, 1931, Serial No. 555,920

2 Claims.

My invention relates to improvements in the chilling and pressing of petroleum stocks containing crystalline Wax, parafiin distillates for example, to separate the contained wax from the 5 stock, to produce so-called neutral oils for example, in chilling and pressing operations in which an added diluent stock, naphtha, kerosene or gas oil for example, is used.

I have discovered that the addition of a chilled diluent stock to a chilled stock containing crystalline wax produces a stock mixture for pressing distinctly more mobile at the pressing temperature than is produced by mixing the diluent stock and the stock containing crystalline wax and then chilling the mixture to the pressing temperature.

In accordance with my invention, the petroleum stock containing crystalline wax is chilled to the pressing temperature, a diluent stock is separately chilled to the pressing temperature, these two chilled stocks are then mixed and the resulting stock mixture is subjected to the pressing operation.

The following comparative examples, one emhodying my invention, will illustrate my invention and the advantages of my invention:

Warm mix 70% of a paraffin distillate having a viscosity of 120 seconds at 100 F. (Saybolt-Universal) is mixed with of naphtha having a boiling range of BOO-400 at a temperature of 90 F., this mixture is chilled to 15 F. and pressed.

. 14.7% on the paralfin distillate of slack wax having a gravity of 38.9 A. P. I. and a melting point of 985 F. is separated.

Cold mix The same paraffin distillate is chilled to a temperature of -15 F. and the same naphtha is separately chilled to a temperature of -15 F., these separately chilled stocks are then mixed in proportions of 70% to 30%, and. this stock mixture is pressed. 18.0% on the paraflin distillate of slack Wax having a gravity of 38.9 A. P. I. and a melting point of 99.0 F. is separated.

Of the two foregoing examples, the second entitled Cold mix embodies my invention.

The filtering rate in the case of this cold mix exceeds that of the warm mix by more than 38%. Comparing the pour tests of the pressed paraffin distillates produced following separation of the diluent naphtha, the pour test of that produced 10 by the cold mix is approximately 4 lower than the pour test of that produced by the warm mix. The crystalline structure of the wax separated in the cold mix is superior to that of the wax separated in the Warm mix, the crystals being more completely formed and the fibers of the crystal structure being longer.

My invention provides advantages with respect to improved filtering rates and with respect to improved structure of the separated crystalline wax and, in the production of pressed stocks of equal pour tests, in some cases affords advantages in reducing refrigeration required.

I claim:

1. In the chilling and pressing of relatively lowviscosity parafiine distillates containing crystalline Wax to separate said wax therefrom, the improvement which comprises chilling the paraffine distillate and separately chilling a diluent stock to the pressing temperature, mixing the chilled paraffine distillate and the chilled diluent stock and pressing the mixture.

2. In the chilling and pressing of relatively low viscosity paraffine distillates containing crystalline wax to separate said wax therefrom, the improvement Which comprises chilling the paraffine distillate and separately chilling a diluent stock to the pressing temperature, mixing the chilled parafiine distillate and the chilled diluent stock 40 in proportions approximating of the former to 30% of the latter and pressing the stock mixture.

EDWARD J GEN MARTIN. 

